Automatic ictttioh-begulatob eos iwtebstal-combtjstiqh ehgihbs



A. W FORBES.

AUTOMATIC :www Hum/mn Ful: mmNAL COMBUSTION ENGINES.

y MlLlC/RHUN HLLD IUL( I3, 1917.

l ,324, 1 48. laltoutcd D00. A(J, 191).

ALLAN W. FORBES, @E WORCESTER, MASSi-CHSETTS.

AUTOMATIC IGNITION-REGULATQR FOR INTERNAL-COMBUSTGN ENGICNES.

Specification of Letters Patent.

Patented Dec. at tiene?.

Application led July 13, 1917. Serial No. 180,377.

To all whom t may concern.:

Be it known that I, ALLAN W. Forests, a citizen of the United States, residing at Worcester, in the county of Worcester and State of Massachusetts, have invented a new and useful Automatic ignition Regulator for Internal-Combustion Engines, of which the following is a specification.

This invention has to do with the regulation of internal combustion engines, and the principal object thereof is to provide automatic means for advancing or retarding the ignition so as to cause it to take place at such a point in the operation of the piston as to bring the highest pressure to bear on the piston during the first part of the working stroke. As is well understood, this is accomplished by igniting at the commencement of the stroke while running at slow speed but before the commencement of the stroke while running at high speed. The invention also involves the provision of very simple mechanism controlled by the pressure in the engine cylinder itself for actuating the spark advancing and retarding mechanism, and means operating periodically with the engine for transferrin the motion to the timer only at the time w en the piston stroke is about to commence.

The invention also involves improvements in details of construction and combinations of. parts as Will appear.

Reference is to be had to the accompanying drawings, in which- Fi re l is a sectional view of one interna combustion engine cylinder showing a preferred means for regulating the timer, an

Fi 2 is a similar view of a modification.

I have shown two forms of the invention, but it is to be understood that in both of them the principle is the same and that there are other ways of carrying it out. By this invention the time of ignition is automatically regulated by the cooperation of two elements, one a device that will operate with the varying pressure in the engine cylinder, and the other one will operate in synchronism with the engine, that is with the crank shaft, cam shaft or other operating.

part of it, and will become operative for the purpose of regulating the timer at a predetermined point in the cycle of operations of the engine, preferably at the time of the start of the working stroke. rllhe regulation of the time of ignition is brought about by the cooperation of these two elements as will appear.

lin the form of the invention shown in Fig. l the engine cylinder 10, containing the usual operating piston 11, is provided with an auxiliary cylinder 12 having in it a small piston 13 having a piston rod 14. This rod is shown as guided by the cylinder 12 and by a bracket 15 cast on or fixed to the cylinder 10. The pressure within the-cylinder 10 forces the piston 18 outwardly against the action of a spring 16 which tends to restore it. riFhe movable member 14 has a surface which may be ot any desired shape and is adapted to coperate with a friction wheel 20 on a shaft 21, @n this shaft is a gear 22 meshing with a gear 23, preferabiy larger so as to reduce the speed. This gear 23 is loose on the shaft 24 which rotates the breaker cam 24H. The gear 23 supports the breaker points 23a and movement of this gear in one direction, as is well understood, advances the spark while movement in the other direction retards it.

The shaft 21 is mounted on an arm 25, shown as provided with an eccentric strap 26 which receives an eccentric or cam 27 on the shaft 28 on which the cams for operating the engine valves are located. lt will be obvious that this arm or movable member can be operated by some other part of the engine moving in synchronism with an engine piston. it lwill be seen that once during each rotation of the shaft 28 the wheel 20 will be advanced into contact with the movable member 14: at the beginning of the engine piston stroke and that the friction wheel 20 and gears constitute connections for varying the timer to advance the spark under certain conditions.

rlhe operation is as follows: When the explosion takes place in the engine cylinder 10 the piston 13 will be forced outwardly to the limit of its stroke. Meantime the movable member 25 is moving in one direction or the other. 1f the ignition is taking place at exactly the right time the eccentric 27 operates in such a Way that when the movable member 14 reaches the limit ofits upward stroke the wheel 20 will have just en- Sii il l? gaged it and Will be drawn away :prom it immediately. ln other Words, the upward niotion imparted to the Wheel at the point of contact While the member 14 is rising will be exactly equal to the downward motion imparted to it while it remains in Contact with it after it commences to descend. Although the duration ot contact between the members le and is always the same, the length oi' motion in either direction will be very small under the conditions just above nfientioned` because the member i4 is coming to rest and reversing at that time. H the ignition takes place too soon the member lll will have risen to its limit and started back, or be ready to start back, before the member 20 touches it and consequently the motion imparted to the 'Wheel 20 will be in one direction and Will be effective to retard the spark. But il the i0'- ynition takes place too late the Wheel 2G will engage the member leV While it isrising and Will move out ot Contact with it before it re verses so that the motion imparted to it will advance the spark. lit "will be understood of course t where trie ignition is nearly correct part of the motion imparted to the Wheel 20 may be in one direction and part in the other, .and yet the greater part will be i etfective to accomplish the desired result but in a smaller degree than in the extreme cases just mentioned.

In the form of the invention shown in Fig. 2 similar conditions prevail, but here the movable members 34 and 35 move in the same direction and by the same causes but their edect on the shaft 24e is obtained in a dii'ierent vvay although the results are the same. The said movable members are provided with paivls 36 and 37 tor engaging teeth. on the circumference of a. Wheel 38 loose on the shaft 24. The movable niembers 34 and 35 are also provided with cross arms as 39 and 40 each connected 'with the pavvl of the opposite member and adapted to throw it out of operation. in this case if ignition is premature the member 34 Will move to lthe top of the stroke first. its it descends its pawl 36 engages the ratchet Wheel and the member 39 pushes the pavvl 37 out of engagement with the ratchet wheel, thus the return motion ot the member 3i will rotate the wheel 38 to retard the spark. While the return motion of the arnisor movable member will not have any eliect.

If ignition is too late the pavvl 37 on its return motion will rotate the ratchet wheel in the other direction to advance the spark. When the ignition is correctly timed both pawls will be pushed awa-y so that the ratchet wheel cannot be operated at all. lthough this ratchet -wheel 38 is shown directly connected to the timer it can be connected indirectly of course.

It will be seen therefore that accordimj,- to this invention the spark is advanced or retarded exactly in accort ance with the actual needs o' the engine and that when the speed is changed the spark will be changed accordingly without any hand regulation. This changing is not related directly to the speed but to the actual need arising from the change in speed.

Although I have illustrated and described only two forms of the invention I am aware of the fact that modifications can be made therein Without departing from the scope ot the invention as expressed in the claims. Therefore I do not wish to be limited to the details and features of construction herein shown and described, butv what l. do claim isz l. The combination with an inter-nal coma bustion engine and a spark timer therefor. of fa. Wheel having connections for varying the time of ignition, means operated by the torce of the explosions for .operating said Wheel, and means operated at a predeterminedperiod for allowing said opera-ting means to be connected with the wheel.

2. The combination with an internal combustion engine and a spark timer therefor, of means for varying the time of ignition, a rotary Wheel -for operating said varying means, means operated by the torce ot the explosion for operating said Wheel, and means operative at a predetermined period of the stroke for disconnecting the operating means from the Wheel.

3. The combination with an internal com bustion engine and a spark timer therefor, of means for varying the time of ignition, a movable member, means connected with the engine cylinder for moving said meinber in one direction While the pressure therein is rising and in another direction While it is falling, means controlled by said movable member for operating said varying means, and means whereby said varying means Will be operatively connected with said movable member only at the beginning of the engine piston stroke.

si. The combination With an internal cornbustion engine and a spark timer therefor, of means for varying the time of ignition, a piston connected with the engine cylinder and adapted to be forced outwardly at the time of greatest pressure therein, means controlled by said piston for directly operating said varying means either on the outward or return stroke thereof, and means connected with the engine and adapted to be operated thereby at the beginning of the engine piston stroke for connecting said varying means with the first named piston so as to be operated thereby.

5. ln an internal combustion engine, the

combination with an engine cylinder having an'auxiliary cylinder, of a piston i-n said auxiliary cylinder, a member movable with said piston, an arm, means connected with the engme for moving sald arm back and member i-n one position of the arm Whereby said Wheel will be turned, and means operated by the Wheel for advancing or retarding the ignition.

In testimony whereofl I have hereunto affixed my signature.

' ALLAN W. FORBES. 

